Referring to FIG. 1, Chinese Patent No. CN101698400B discloses a conventional angle regulation device for mounting of a radar detector 60. The conventional angle regulation device includes an upper casing 10, a lower casing 20, an angle transducer 30, a driving unit 40 and an adjusting unit 50. The upper casing 10 is fixed to a head portion of a vehicle. The lower casing 20 is pivoted to the upper casing through a pivot axle 201, and cooperates with the upper casing 10 to define a mounting space 70 therebetween. The radar detector 60 is mounted fixedly to the lower casing 20 and is received in the mounting space 70. The driving unit 40 includes a motor 401 that is mounted in the upper casing 10, and a nut 402 that is driven rotatably by the motor 401. The adjusting unit 50 includes screw 501 that engages drivingly the nut 402 and that has an end connected pivotally to the lower casing 20, and a coil spring 502 that is sleeved on the screw 501 and that has opposite ends abutting respectively against the upper and lower casings 10, 20. The angle transducer 30 is mounted in the upper casing 10 for positioning the motor 401. When an orientation sensor (not shown) fixed to the head portion of the vehicle senses tilt of the upper casing 10, the motor 401 is energized to drive rotation of the not 402, so as to move the screw 501 in a vertical direction (A). As such, an assembly of the lower casing 20 and the radar detector 60 can be kept at an optimal angle.
However, since the screw 501 is configured to adjust the tilt of the lower casing 20 directly, the resolution of the adjustment of the conventional angle regulation device is relative low. Moreover, the angle transducer 30 has a relatively short service life, so that the conventional angle regulation device needs to be repaired frequently.